Estrogen May Affect the Maintenance of Stemness, Rather Than Differentiation, of Human Embryonic Stem Cells

Abstract

Objective: Estradiol (E2) is the foremost steroid hormone for the early embryos proliferating and developing in human pregnancy. With regard to its physiological functions which have not yet been fully elucidated, human embryonic stem (hES) cells may provide an alternative experimental model for investigation of development in early embryonic stage. We designed this study to investigate the effects of 17-β E2 in hES cell and differentiated embryoid bodies (EBs). Methods: The undifferentiated hES cells (SNUhES3-derived from Seoul National University Hospital) were incubated with the different 17-β E2 concentrations at 0, 1, 10 μM for 48 hours before EBs formation and E2 was continually treated for 8 days after EBs formation. RT-PCR were performed at the undifferentiated hES and the induced EBs (day 4 and 8) stages with primers of ectoderm (NFH, Dopamine β Hydroxylase), mesoderm (Nkx2.5, Brachyury, Myogenin), endoderm (αFP, Albumin, Aldorase B) and pluripotent (Oct-4, NANOG, SOX2) markers. Results: The administration of E2 did not show a significant effect on the differentiation of hES cells. Compared to its effects on hES cells, supplementation of E2 onto EBs induced up-regulation of stemness-related genes in a dose-dependent manner, evident with expressions of Nanog and Sox2. Conclusion: E2 may have effects not on the differentiation of hES, but on the down-regulation of stemness-related genes in EBs. Further studies using other stem cell lines are necessary to confi rm our results. (SC1150 and No. 2009-0071924).